League Table Positions

Posted in Education, Football with tags , , , , , , , on May 26, 2015 by telescoper

Among the things I didn’t have time to blog about over a very busy Bank Holiday Weekend was the finish of the English Premiership season. I haven’t posted much about my own team, Newcastle United, this season because I haven’t been able to think of anything particularly positive to say. Since Alan Pardew quit in January to join Crystal Palace, Newcastle slumped to such an alarming extent that they went into their last game of the season (against West Ham) just two points above the drop zone. Had they lost their game, which did not seem unlikely on the basis of their recent form, and had Hull won against Manchester United, which did not seem unlikely on the grounds that Man Utd wwould finish in 4th place whatever happened in that game, then Newcastle would be relegated to the Championship. In the event, however, Newcastle won 2-0 which made them safe while Hull could only draw 0-0 which meant that Newcastle would have survived even if they had lost against West Ham. Moreover, Sunderland also lost their last game, which meant that the final Premier League Table looked like this:

Premiership_League

(courtesy of the BBC Website). The important places are 15 and 16, obviously. The natural order of things has been restored….

Another League Table came out over the Bank Holiday. This was the annual Guardian University Guide. I’m deeply sceptical of the value of these league tables, but there’s no question that they’re very important to potential students so we have to take them seriously. This year was pretty good for Sussex as far as the Guardian Table is concerned: the University of Sussex rose to 19th place overall and the two departments of the School of Mathematical and Physical Sciences both improved: Physics & Astronomy is back in the top 10 (at number 9, up from 11th place last year) and Mathematics rose 22 places to take 21st place. Gratifyingly, both finished well above Sunderland.

While these results are good news in themselves, at least around my neck of the woods, as they will probably lead to increased applications to Sussex from students next year, it is important to look behind the simplistic narrative of “improvements”. Since last year there have been several substantial changes to the Guardian’s methodology. The weighting given to “spend-per-student” has been reduced from 15% to 10% of the overall score and the method of calculating “value added” has excluded specific predictions based on “non-tariff” students (i.e. those without UK entry qualifications, especially A-levels). What the Guardian consistently fails to do is explain the relative size of the effect of arbitrary methodological changes on its tables compared to actual changes in, e.g., cash spent per student.

Imagine the outrage there would be if football teams were not told until the end of a Premier League season how many points would be awarded for a win….

Laurie Anderson – All the Animals

Posted in Art, Music with tags , , on May 25, 2015 by telescoper

Taking a short break from the combination of marking examinations and listening to cricket which has been my Bank Holiday Monday so far, so I thought I’d post a brief report on the show I went to last night, which happened to be the last night of this year’s Brighton Festival.

All the Animals was a show put together especially for this year’s Brighton Festival by renowned performance artist Laurie Anderson. She is most famous (at least in the UK) for the amazing record O Superman which was a smash hit in 1981; I posted about that on this blog here. A large number of last night’s audience members were clearly devout Laurie Anderson fans but I’ve never seen one of her live shows so wasn’t sure what to expect.

It turned out to be very much a one-woman show, with Laurie Anderson alone on stage. The show consisted of her telling stories about various animals, including her own pet terrier, Lula Belle, who is now sadly deceased. In between the stories there were musical interludes, with herself performing on an electric violin with various digital effects thrown in, and sometimes she accompanied herself as she performed the stories. The show was shot through with a wry humour and Laurie Anderson herself came across as a very engaging personality.

I had been told that her performances were often dazzling multimedia events, but this turned out not to be like that at all. The big screen at the back of the stage was only used a couple of times, once to show excerpts from a list of extinct animal species and once to show a couple of Youtube clips of Lula Belle. There were no dramatic lighting or other effects either. It was all very low key really. Far from the multimedia extravaganza I had anticipated.

There was enthusiastic applause at the end of the show, but to be honest I felt a little disappointed. Don’t get me wrong: I enjoyed the show, and still think Laurie Anderson is a really interesting artist but I suppose I just built up in myself an expectation of something with a more exciting visual element.

So that’s the end of this year’s Brighton Festival. Still, yesterday I posted the following tweet:

I guess all three predictions proved false. England didn’t lose on Sunday and indeed are very much favourites to win the Test match as I write this. Newcastle United won their game against West Ham and avoided relegation to the Championship. And Laurie Anderson, though definitely interesting, didn’t quite qualify as “fabulous”…

Another Lord’s Day

Posted in Cricket with tags , , , , , on May 24, 2015 by telescoper

Just time for a quick post to record the fact that yesterday I made my annual pilgrimage to Lord’s Cricket Ground to watch the third day’s play of the First  Test between England and New Zealand.  On previous occasions I’ve had to make the trip from Cardiff to Paddington and back to take in a day at the Test, so had to get up at the crack of dawn, but this time I was travelling from Brighton which is a significantly shorter trip, so I only had to get up at 7 or so. Anyway, I got to the ground in time to have a bacon sandwich and a coffee before play started, with the added pleasure of listening to the jazz band as I consumed both items.

England had batted first in this game, and were on the brink of disaster at 30 for 4 at one stage, but recovered well to finish on 389 all out. Joe Root, Ben Stokes and Moeen Ali all made valuable runs in the middle order. Their performance was put into perspective by New Zealand, however, who had reached 303 for 2 at the end of the first day. It’s hard to say whether it was New Zealand’s strength in batting or England’s lacklustre bowling that was primarily responsible. I suspect it was a bit of both. Talk around the ground was if and when New Zealand might declare. I didn’t think I would declare on a score less than 600, even if tempted to have a go at the England batsman for 30 minutes in the evening, but that speculation turned out to be irrelevant.

Anyway on a cool and overcast morning, New Zealand resumed with Taylor and Williamson at the crease and England desperately needing to take quick wickets. The first breakthrough came after about 40 minutes, with Taylor well caught by wicketkeeper Buttler off the bowling of Stuart Broad. That served to bring in dangerman Brendan McCullum, who promptly hit his first ball for four through the covers. He continued to play his shots but never looked really convincing, eventually getting out to a wild shot off England’s debutant bowler Mark Wood, but not before he’d scored 42 runs at a brisk pace while Williamson at the other end continued to his century in much more sedate fashion.

Light drizzle had started to fall early on in the morning and shortly after McCullum was out it became much heavier. The players took an early lunch and play did not resume until 2.45pm, meaning that over an hour was lost. During the extended lunch interval I took a stroll around the ground, bought an expensive burger, and noted the large number of representatives of the Brigade of Gurkhas, who were collecting money for the Nepal Earthquake Appeal. Here are some of them making use of their vouchers in the Food Village:

Lords_Ghurkas

When play resumed, England quickly took another wicket, that of Anderson, at which point New Zealand were 420 for 5. Wicketkeeper Watling (who had an injury from the first innings) came to the crease and look all at sea, frequently playing and missing and surviving two umpire reviews. He led a charmed life however and ended up 61 not out when the New Zealand innings closed at 523 all out.

One interesting fact about this innings was that “Extras” scored 67. Quite a lot of those were leg-byes, but the number of wides and byes was quite embarrassing. Wicket-keeper Buttler did take a couple of fine catches, but he wasn’t as tidy as one would expect at Test level. England also dropped three catches in the field. New Zealand only added 212 runs for their last 8 wickets, which wasn’t as bad as it could have been for England but it could have been better too. I wasn’t impressed with their bowling, either. Neither Anderson nor Broad looked particularly dangerous, although both took wickets. Wood was erratic too, straying down the legside far too often, but he did improve in his second spell and managed to take three wickets. I think Moeen was the steadiest and most impressive bowler, actually. He also took three, including that of Williamson whose excellent innings ended on  132.

I took this picture from my vantage point in the Warner Stand  just a few minutes before the last New Zealand wicket fell:

Lords_NZ

You can see it was still quite gloomy and dark.

Incidentally, the Warner Stand is to be knocked down at the end of this season (in September 2015) and rebuilt much bigger and snazzier. I’ve got used to watching cricket from there during my occasional trips to Lord’s so I feel a little bit sad about its impending demise. On the other hand, it does need a bit of modernisation so perhaps it’s all for the best. The first phase of the rebuild should be ready for next season so I look forward to seeing what the new stand looks like in a year or so’s time.

England came out to bat with play extended until 7.30 to make up for the time lost for rain. Lyth faced the first ball, which was short. He played a hook shot which he mistimed. It went uppishly past the fielder at short midwicket for four, but it was a very risky shot to play at the very start of the innings given England’s situation and it made me worry about his temperament. He hit another couple of boundaries and then departed for 12, caught behind. Ballance  came in, faced twelve deliveries and departed, clean bowled, without troubling the scorers. At that point England were in deep trouble at 25-2, still needing over a hundred runs to make New Zealand bat again. With the weather brightening up considerably, Bell and Cook steadied the ship a little and no more wickets were lost before the close of play. I had to leave before the close in order to get the train back to Brighton but the day ended with England on 75-2.

I think New Zealand will win this game, for the simple reason that their bowling, fielding and batting are all better than England’s.  The biggest worry for England is their batting at the top of the order, which is far too fragile, but the bowling lacks penetration and the fielding is sloppy.  It doesn’t bode well for the forthcoming Ashes series but more immediately it doesn’t bode well for Alastair Cook’s position as England captain. But who could replace him?

UPDATE, 7pm Sunday. Contrary to my pessimistic assessment, England played very well on Day 4. Cook batted all day, ending on 153 not out but the star of the show was Ben Stokes who scored the fastest century ever in a test at Lord’s (85 balls). With England on 429 for 6, a lead of 295, any result is possible. England need to bat until about lunch to make the game safe, and only then think about winning it.

UPDATE, 5.38pm Monday. The morning didn’t go entirely England’s way. They only reached 478 all out, a lead of 344. However, New Zealand were in deep trouble straight away, losing both openers without a run on the board. They were in even deeper trouble a bit later when they slumped to 12-3 but then staged a mini-recovery only for two quick wickets to fall taking them to 61-5. There then followed an excellent partnership of 107 between Anderson and Watling who at one point looked like wresting the initiative away from England. Then both fell in quick succession and were soon followed by Craig and Southee. As I write this, New Zealand are 200 for 9. England need one more wicket and have 15 overs left to get it, with two tailenders at the crease.

UPDATE, 6.03pm Monday. It seemed to take forever to come, but Moeen has just caught last man Boult off the bowling of Broad. New Zealand all out for 220 and England win by 124 runs, a victory I simply could not have imagined when I left Lord’s on Saturday. I’ve never been happier to be proved wrong!

This has been one of the great Test matches and I’m really happy I was there for part of it – even if it was only one day! Well played both teams for making such an excellent game of it. Long live Test cricket. There’s nothing like it!

The Diary of One who Disappeared

Posted in Music with tags , , , , , , , on May 22, 2015 by telescoper

At the end of a very busy day before I go home and vegetate, I only just have time for a quick post about the concert I attended last night in St George’s Church, Kemptown. It was a convenient venue for me as it is just at the end of my street; my polling station for the recent elections was there too.

Anyway, the title of the concert is taken from the song cycle of the same name composed by Leoš Janáček. It’s a sequence of 21 poems about a young man who falls for seductive gypsy girl and ends up running away from home to be with her, and care for the baby son she turns out at the end of the cycle to have born. There’s also a very tempestuous piano interlude, labelled Intermezzo Erotico in the programme, which (presumably) depicts the circumstances in which the baby was conceived. This work was performed by mezzo-soprano Anna Huntley and tenor Robert Murray accompanied by James Baillieu at the piano (who also played the piano at the recital I attended last week). Three female voices also took part in a few of these songs; they were hidden away in the gallery so it was quite a surprise when they joined in.

Despite being a big fan of Janáček I’ve never heard this music before, and I found it absolutely wonderful. It involves many abrupt and unexpected changes of mood, with soome simple folk-like melodies juxtaposed with much more disturbed and fragmented musical language. At the end, when the young man reveals that he has a son, the tenor reaches up for two stunning top Cs which took me completely by surprise and sent cold shivers down my spine. I must get a recording of this work. As soon as it had finished I wanted to listen to it all over again.

The Diary of One who Disappeared formed the second half of the concert. The first was also very varied and interesting. We began with he two principal singers taking turns at performing a selection of six from a well-known set of 49 Deutsche Volkslieder by Johannes Brahms. Then Robert Murray – who looks somewhat disconcertingly like Shane Warne – performed the Seven Sonnets of Michelangelo by Benjamin Britten (his Opus 22). These were the first pieces Britten composed specifically for the voice of his partner Peter Pears and were written way back in 1940. They’re all poems about love in its various forms and I think they’re wonderful, especially Sonnet XXX:

Veggio co’ bei vostri occhi un dolce lume,
Che co’ miei ciechi già veder non posso;
Porto co’ vostri piedi un pondo addosso,
Che de’ mie zoppi non è già costume.
Volo con le vostr’ale senza piume;
Col vostr’ingegno al ciel sempre son mosso;
Dal vostr’arbitrio son pallido e rosso,
Freddo al sol, caldo alle più fredde brume.
Nel voler vostro è sol la voglia mia,
I mie’ pensier nel vostro cor si fanno,
Nel vostro fiato son le mie parole.
Come luna da sè sol par ch’io sia;
Chè gli occhi nostri in ciel veder non sanno
Se non quel tanto che n’accende il sole.

It’s a fine poem in itself but Britten’s setting of it is both beautiful and imaginative. I’m guessing that it’s extremely difficult to sing because the vocal line is very complex and has some very challenging intervals. You can almost imagine it being part of a bel canto opera…

The first half of the concert closed with the Seven Gypsy Songs (Opus 55) by
Antonín Dvořák, by far the most famous of which is Songs My Mother Taught Me.

It was a very fine recital with some lovely music, beautifully sung. In fact the singing was so nice a blackbird outside the church decided to join in during the first half. It was a nicely balanced programme tied together by two recurrent themes: Gypsies and love (and sometimes both at the same time). TheI particularly enjoyed the blend of familiar and unfamiliar. For example, although I know the Sonnets by Britten I’ve only ever heard the classic Britten-Pears version so it was interesting to hear it performed by a very different singer.

Phlogiston, Dark Energy and Modified Levity

Posted in History, The Universe and Stuff with tags , , on May 21, 2015 by telescoper

What happens when something burns?

Had you aslked a seventeenth-century scientist that question and the chances are the answer would  have involved the word phlogiston, a name derived from the Greek  φλογιστόν, meaning “burning up”. This “fiery principle” or “element” was supposed to be present in all combustible materials and the idea was that it was released into air whenever any such stuff was ignited. The act of burning was thought to separate the phlogiston from the dephlogisticated “true” form of the material, also known as calx.

The phlogiston theory held sway until  the late 18th Century, when Antoine Lavoisier demonstrated that combustion results in an increase in weight of the material being burned. This poses a serious problem if burning also involves the loss of phlogiston unless phlogiston has negative weight. However, many serious scientists of the 18th Century, such as Georg Ernst Stahl, had already suggested that phlogiston might have negative weight or, as he put it, “levity”. Nowadays we would probably say “anti-gravity”.

Eventually, Joseph Priestley discovered what actually combines with materials during combustion:  oxygen. Instead of becoming dephlogisticated, things become oxidised by fixing oxygen from air, which is why their weight increases. It’s worth mentioning, though, the name that Priestley used for oxygen was in fact “dephlogisticated air” (because it was capable of combining more extensively with phlogiston than ordinary air). He  remained a phlogistonian longer after making the discovery that should have killed the theory.

So why am I rambling on about a scientific theory that has been defunct for more than two centuries?

Well,   there just might be a lesson from history about the state of modern cosmology. Not long ago I gave a talk in the fine city of Bath on the topic of Dark Energy and its Discontents. For the cosmologically uninitiated, the standard cosmological model involves the hypothesis that about 75% of the energy budget of the Universe is in the form of this “dark energy”.

Dark energy is needed to reconcile three basic measurements: (i) the brightness distant supernovae that seem to indicate the Universe is accelerating (which is where the anti-gravity comes in); (ii) the cosmic microwave background that suggests the Universe has flat spatial sections; and (iii) the direct estimates of the mass associated with galaxy clusters that accounts for about 25% of the mass needed to close the Universe. A universe without dark energy appears not to be able to account for these three observations simultaneously within our current understanding of gravity as obtained from Einstein’s theory of general relativity.

We don’t know much about what this dark energy is, except that in order to make our current understanding work out it has to produce an effect something like anti-gravity, vaguely reminiscent of the “negative weight” hypothesis mentioned above. In most theories, the dark energy component does this by violating the strong energy condition of general relativity. Alternatively, it might also be accounted for by modifying our theory of gravity in such a way that accounts for anti-gravity in some other way. In the light of the discussion above maybe what we need is a new theory of levity? In other words, maybe we’re taking gravity too seriously?

Anyway, I don’t mind admitting how uncomfortable this dark energy makes me feel. It makes me even more uncomfortable that such an enormous  industry has grown up around it and that its existence is accepted unquestioningly by so many modern cosmologists. Isn’t there a chance that, with the benefit of hindsight, future generations will look back on dark energy in the same way that we now see the phlogiston theory?

Or maybe the dark energy really is phlogiston. That’s got to be worth a paper!

One More for the Bad Statistics in Astronomy File…

Posted in Bad Statistics, The Universe and Stuff with tags , , , , , on May 20, 2015 by telescoper

It’s been a while since I last posted anything in the file marked Bad Statistics, but I can remedy that this morning with a comment or two on the following paper by Robertson et al. which I found on the arXiv via the Astrostatistics Facebook page. It’s called Stellar activity mimics a habitable-zone planet around Kapteyn’s star and it the abstract is as follows:

Kapteyn’s star is an old M subdwarf believed to be a member of the Galactic halo population of stars. A recent study has claimed the existence of two super-Earth planets around the star based on radial velocity (RV) observations. The innermost of these candidate planets–Kapteyn b (P = 48 days)–resides within the circumstellar habitable zone. Given recent progress in understanding the impact of stellar activity in detecting planetary signals, we have analyzed the observed HARPS data for signatures of stellar activity. We find that while Kapteyn’s star is photometrically very stable, a suite of spectral activity indices reveals a large-amplitude rotation signal, and we determine the stellar rotation period to be 143 days. The spectral activity tracers are strongly correlated with the purported RV signal of “planet b,” and the 48-day period is an integer fraction (1/3) of the stellar rotation period. We conclude that Kapteyn b is not a planet in the Habitable Zone, but an artifact of stellar activity.

It’s not really my area of specialism but it seemed an interesting conclusions so I had a skim through the rest of the paper. Here’s the pertinent figure, Figure 3,

bad_stat_figure

It looks like difficult data to do a correlation analysis on and there are lots of questions to be asked  about  the form of the errors and how the bunching of the data is handled, to give just two examples.I’d like to have seen a much more comprehensive discussion of this in the paper. In particular the statistic chosen to measure the correlation between variates is the Pearson product-moment correlation coefficient, which is intended to measure linear association between variables. There may indeed be correlations in the plots shown above, but it doesn’t look to me that a straight line fit characterizes it very well. It looks to me in some of the  cases that there are simply two groups of data points…

However, that’s not the real reason for flagging this one up. The real reason is the following statement in the text:

bad_stat_text

Aargh!

No matter how the p-value is arrived at (see comments above), it says nothing about the “probability of no correlation”. This is an error which is sadly commonplace throughout the scientific literature, not just astronomy.  The point is that the p-value relates to the probability that the given value of the test statistic (in this case the Pearson product-moment correlation coefficient, r) would arise by chace in the sample if the null hypothesis H (in this case that the two variates are uncorrelated) were true. In other words it relates to P(r|H). It does not tells us anything directly about the probability of H. That would require the use of Bayes’ Theorem. If you want to say anything at all about the probability of a hypothesis being true or not you should use a Bayesian approach. And if you don’t want to say anything about the probability of a hypothesis being true or not then what are you trying to do anyway?

If I had my way I would ban p-values altogether, but it people are going to use them I do wish they would be more careful about the statements make about them.

Dust, by Phyllis King

Posted in Poetry with tags , , on May 19, 2015 by telescoper

I do not know what dust is.
I do not know where it comes from.
I only know that it settles on things.
I cannot see it in the air or watch it fall.
Sometimes I’m home all day
But I never see it sliding about looking for a place to rest when my back is turned.
Does it wait ’til I go out?
Or does it happen in the night when I go to sleep?
Dust is not fussy about the places it chooses
Though it seems to prefer still objects.
Sometimes, out of kindness, I let it lie for weeks.
On some places it will lie forever
However, dust holds no grudges and once removed
It will always return in a friendly way.

by Phyllis April King

Follow

Get every new post delivered to your Inbox.

Join 4,141 other followers